A dental patient unhappy with a bill totaling nearly $4,800 is suing to overturn a contract he signed banning him from criticizing his dentist.

Public Citizen filed suit on behalf of Robert Lee, who now lives in Huntingtown, Md., according to Ars Technica’s Law & Disorder blog, the New York Daily News, MSNBC.com and a press release. He criticized his Manhattan dentist, Dr. Stacy Makhnevich, on Yelp and other online sites, saying she overbilled him and advising readers to “avoid at all cost!”

According to the suit (PDF), Makhnevich will not perform dental work unless patients sign a contract waiving any right to publicly comment on the services and assigning all copyrights in online comments to herself. The contract says the dentist will refrain from marketing confidential information about the patient in exchange for the assignment of copyright. But such marketing is already prohibited by the federal Health Insurance Portability and Accountability Act, the suit says.

Lee claims he signed the contract while he was in pain. He was billed $800 for draining a tooth and nearly $4,000 for filling it; the latter procedure should have cost about $200, the suit alleges. When Lee experienced problems getting the bill paid by his insurer, he criticized Makhnevich online. Her response: She sought $100 a day for copyright infringement.

The suit contends the contract is unconscionable and misuses copyright law to suppress expression. The contract’s promise to refrain from medical disclosures in exchange for the copyright is a promise to foreswear illegal activity and does not constitute valid consideration, the suit says. It also contends public comments are a fair use under the copyright law.

The contract was prepared by a North Carolina company, Medical Justice Services Inc., which is now advising its customers to stop using the agreements, Ars Technica says.